Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online). Mark Zegarelli
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СКАЧАТЬ between the two problems is the placement of the parentheses, but because both operations are addition, moving the parentheses doesn’t change the answer.

      Q. Solve math

      A. 24 and 24. To solve math first do the operation inside the parentheses — that is, math

math

      Finish by multiplying math

      To solve math first do the operation inside the parentheses — that is, math

math

      Finish by multiplying math. No matter how you group the multiplication, the answer is the same.

      Q. Solve math

      A. 410. The last two numbers are small, so place parentheses around these numbers:

math

      First, do the multiplication inside the parentheses:

math

      Now you can easily multiply math

      5Your turn Find the value of math

      6 Find the value of math

      7 Solve the following two problems:

      (a) math

      (b) math

      Do the parentheses make a difference in the answers?

      8 Solve the following two problems:

      (a) math

      (b) math

      Do the parentheses make a difference in the answers?

      9 Solve the following two problems:

      (a) math

      (b) math

      Do the parentheses make a difference in the answers?

      10 Find the value of math. (Hint: Use the associative property for multiplication to make the problem easier.)

      Distribution to lighten the load

      If you’ve ever tried to carry a heavy bag of groceries, you may have found that distributing the contents into two smaller bags is helpful. This same concept also works for multiplication.

      For example, suppose you want to multiply these two numbers:

math

      You can go ahead and just multiply them, but distribution provides a different way to think about the problem that you may find easier. Because 101 = 100 + 1, you can split this problem into two easier problems, as follows:

math

      You take the number outside the parentheses, multiply it by each number inside the parentheses one at a time, and then add the products. At this point, you may be able to calculate the two multiplications in your head and then add them up easily:

math

      Distribution becomes even more useful when you get to algebra in Unit 7.

      ExampleQ. Multiply math using distribution:

math

      A. math

      11Your turn Multiply math using distribution:

math

      12 Multiply math using distribution:

math

      13 Multiply math using distribution:

math

      14 Multiply СКАЧАТЬ